Exam 2

Question 1

signal transduction

Answer 1

converts information from signal into cellular response

Question 2

ligand

Answer 2

binds to receptor protein making the cell respond; the signaling molecule

Question 3

Animal cell signals

Answer 3

• Hormones, peptide (insulin) or steroid (estrogen)
• Neurotransmitters (catecholamine)
• Cytokines (interleukins)

Question 4

Plant cell signals

Answer 4

• Hormones (auxin, gibberellin, brassinosteroid)
• Red light
• Blue light

Question 5

intracellular receptor

Answer 5

• steroid hormones
• cytoplasm
• nonpolar; bind to lipid-soluble ligands (hydrophobic)
• can easily cross plasma membrane and bind to a cytoplasmic protein

Question 6

cell surface/membrane receptor

Answer 6

3 types:

1. channel linked- ion channel that opens in response to a ligand
2. enzymatic- an enzyme activated by ligand
3. G protein-coupled- bound to GTP and assists in transmitting signal
   - water soluble; cannot cross membrane
   - outside cell (cytoplasm + environment)

Question 7

How to turn receptors on/off

Answer 7

1. On: Add a phosphate from ATP (Kinase)
   Off: Remove a phosphate (phosphatase)
2. On: add GTP (GEF trades GDP for GTP)
   Off: release P (GAP)

Question 8

second messenger

Answer 8

alter behavior of cellular proteins by binding to them and changing their shape

• cyclic-AMP(cAMP)
• calcium/calmodulin

Question 9

Steroid receptor’s 3 domains

Answer 9

1. hormone-binding
2. DNA- binding
3. a domain that can interact with coactivators to affect the level of gene transcription

Question 10

substrate

Answer 10

molecule that undergo reaction

Question 11

active site

Answer 11

region of the enzyme that binds to substrate

Question 12

allosteric enzymes

Answer 12

possess allosteric site where molecules other than the substrate can bind
-active or inactive site

Question 13

cofactor

Answer 13

usually metal ions that bind to a protein to make it active

Question 14

coenzyme

Answer 14

• non-protein organic molecules

- electron donor or acceptor in redox reaction

Question 15

biochemical pathway

Answer 15

a series of reactions in which a product of one reaction becomes the substrate for the next

Question 16

feedback inhibition

Answer 16

the end product is an allosteric inhibitor of an earlier enzyme in the pathway

Question 17

anabolism

Answer 17

chemical reactions that expend energy to make new bonds (synthesis)

Question 18

catabolism

Answer 18

chemical reactions that harvest energy when bonds are broken (breakdown) (to make ATP)

Question 19

Cellular respiration

Answer 19

• process by which energy is harvested (process of making ATP)
• exergonic
• leads to redox, moves electrons, makes ATP

Question 20

aerobic respiration

Answer 20

final electron receptor is O2 and produces H2O
(each step is lower energy than the next)
Delta G= negative
-everything we learned

Question 21

chemiosis

Answer 21

using a proton gradient to make ATP

Question 22

thylakoid membrane

Answer 22

internal membrane arranged in flatten discs containing chlorophyll

Question 23

antenna complex

Answer 23

• captures photons from sunlight

- reaction center and accessory pigments

Question 24

photosystem

Answer 24

photosynthetic pigments are clustered together in the thylakoid membrane

Question 25

cyclic phosphorylation

Answer 25

- photons added exciting electrons then electrons are returned back - ATP (only product) made by chemiosis (gradient) - electrons come from pigments

Question 26

photorespiration

Answer 26

- when hot storm openings close cutting off CO2 causing it to bind to rubisco - no glucose; not useful; CO2 lost - chloroplast-> peroxisome-> mitochondrion

Question 27

cytokinesis

Answer 27

splitting of the cells

Question 28

condensin

Answer 28

protein for super coil

Question 29

histones

Answer 29

proteins that cluster in 8 to make a nucleosome

Question 30

chromatin

Answer 30

DNA and protein

Question 31

kinetochore

Answer 31

attachment point for spindle

Question 32

cohesin

Answer 32

protein that holds chromosomes together

Question 33

cyclins`

Answer 33

proteins produced in sychrony with cell cycle | -regulate passage of cell through check points

Question 34

CDK

Answer 34

- cyclin-dependent kinases - enzymes that drive cell - activate only when bound by a cyclin

Question 35

how to activate CDK

Answer 35

-kinases add 2 phosphate -phosphatase clips off one phosphate (kinase cascade)

Question 36

kinase cascade

Answer 36

- phosphates are added to kinase that goes to receptor turning it on - one signal protein gets phosphorylated then transfers phosphate to next signal protein

Question 37

protein gradient

Answer 37

ATP synthase- protons move back into matrix to make ATP (h+) (oxygen is needed)

Question 38

phragmoplast

Answer 38

formed by microtubules; makes cell plate (new cell wall)